The goal of this project is to improve our knowledge of, and ability to measure, adult mortality in the developing world. Many developing countries lack conventional data sources permitting the regular measurement of mortality. Valid substitute methods for measuring mortality in childhood have been developed, and applied across the majority of developing countries. Success with development of substitute methods for adult mortality has been more limited, and no cross-national comparative reviews of age patterns and trends have been carried out, despite the fact that extensive data exist. This project will compile data sets relevant to the measurement of adult mortality for selected countries representing all regions of the developing world. We will evaluate the data sets and carry out adjustments as necessary, explore and quantify the performance of the methodologies available for evaluating such data sets and deriving mortality estimates from them, and develop new methodologies as necessary to improve estimation validity. Standard methods will be developed to assess the uncertainty affecting all estimates, and to define plausible ranges around observed mortality rates within which true rates are expected to lie. The validated data will then be used to compute life stables for the selected countries for different time points. A web-accessible data base including both raw data and final life tables will be created in parallel with the existing Berkeley Mortality questions: (a) how do patterns and trends of mortality in LDCs today compare with the historical experience of now- developed countries as observed in the BMD? (B) what has been the impact of economic reversals on mortality trends? And (c) how large has been the mortality impact of the HIV/AIDS epidemic? The mortality information for selected countries will also be used as a basis for developing region-specific distributions of deaths by age as a key input to studying burden of disease.